I cannot install anything in the Ubuntu Software Center without it telling me that it's an "untrusted package." I also went to the software sources to "reload" but it gave me this:
Could not download all repository indexes The repository may no longer be available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and ensure the repository address in the preferences is correct. Failed to fetch http://ppa.launchpad.net/ubuntu-advertising/uadvt/dists/<source.changes>/ubuntu/maverick/binary-i386/Packages.gz 404 Not Found Failed to fetch http://ppa.launchpad.net/ubuntu-advertising/uadvt/dists/<source.changes>/ubuntu/main/binary-i386/Packages.gz 404 Not Found Some index files failed to download, they have been ignored, or old ones used instead.